Aircraft Accident/Incident Report

Chandler, Arizona 85225
Wednesday, May 22, 1996 10:15 MST

NTSB Narrative Summary Released at Completion of Accident

The dual student began to apply power during a normal approach to landing when the main rotor rpm needle went into the yellow arc on the engine gauge. The CFI applied full power but the rpm continued into the lower portion of the arc. The helicopter made ground contact with low rotor rpm and the right skid collapsed. The helicopter bounced and rolled over. Examination of the engine revealed that a section of the piston from the dome to the first ring groove had broken away. The upper ring was broke and pieces were found in the combustion area. Normal carbon buildup was found on the cylinder sleeve above the top ring surface except in the area of the piston breakage, indicating that the engine had been operating for a period of time after the damage had taken place and before the accident.

NTSB Probable Cause Narrative

a loss of engine power due to a failed piston and piston ring in a critical phase of flight.

Event Information

Type of Event Accident
Event Date 5/22/1996
Event Day of the Week Wednesday
Time of Event 1015
Event Time Zone Mountain Standard Time
Event City CHANDLER
Event State ARIZONA
Event Country --
Zipcode of the event site 85225
Event Date Year 1996
Event Date Month 5
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport
Event Location Nearest Airport ID
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness Unknown
Investigator's weather source Pilot
Time of the weather observation 0
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID
Elevation of weather observation facility 0
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 30
Air Temperature at event time (in degrees celsius) --
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) 0
Variable Wind Indicator Unknown
Wind Speed (knots) 0
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) --
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor --
Injury Total None 2
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 304
NTSB Notification Source --
NTSB Notification Date May 30 1996 12:00AM
NTSB Notification Time 754
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 8 2000 10:00AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N89678
NTSB Number LAX96LA210
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Rotorway
Aircraft Model EXEC 9
Aircraft Series Identifier EXEC 9
Aircraft Serial Number RI 5026
Certified Max Gross Weight 1425
Aircraft Category Helicopter
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 2
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection 100 Hour
Date of Last Inspection May 22 1996 12:00AM
Airframe hours since last inspection 3
Airframe Hours --
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name COBB INTERNATIONAL, INC
Aircraft Owner Street Address 4141 W CHANDLER BLVD
Aircraft Owner City CHANDLER
Aircraft Owner State AZ
Aircraft Owner Country
Aircraft Owner Zipcode 85225
Operator is an individual? --
Operator Name
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address
Operator City
Operator State
Operator Country
Operator Zip code
Operator Code
Owner has at least one certificate None
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Instructional
Second Pilot on Board Yes
Departure Point Same as Event Yes
Departure Airport Code P19
Departure City
Departure State
Departure Country
Departure Time 900
Departure Time Zone MST
Destination Same as Local Flt dest & departure same, accident can occur anywhere
Destination Airport Code
Destination City
Destination State
Destination Country
Specific Phase of Flight Landing
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:30AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --